A growing body of evidence suggests that the shared use of drug preparation materials has an important role in the transmission of HIV and HCV among IDUs. Systematic observations of drug preparation episodes suggest that the main source of contamination of non-syringe materials stems from the common practice of using an injection syringe to pull up water and expel it into a cooker, and to draw up the drug solution from the cooker and distribute it to other syringes. In our preliminary research we have identified the practices by which injection syringes make contact with the other preparation materials and the types of water dispensers and preparation syringes that have the potential to enable IDUs to avoid using injection syringes to prepare and distribute drug solutions. We propose to work with IDUs and community outreach workers in San Juan, Puerto Rico, to develop new practices and to identify new preparation materials that can effectively promote the separation of injection syringes from the process of preparing drug solutions. Research activities will be implemented in three phases: First, we will organize a team comprised of IDUs and community outreach workers who will bench-test candidate materials to identify and select the materials most suitable to permit the separation of the injection syringes from the process of preparing drug solutions. In the second phase, we will develop instructional and promotional materials with which to communicate the risks of using injection syringes in the preparation of drug solutions, and demonstrate to IDUs how the new water dispensers and preparation syringes can be used to keep the injection syringe from making contact with the preparation materials. Finally, we propose to conduct a small-scale field trial in three neighborhoods among approximately 75 IDUs to examine the extent to which the use of syringes in the preparation of drug solutions is reduced and the new materials are adopted, and to assess the safety, performance, and costs of the new materials. The findings and results from the proposed exploratory research will provide the needed knowledge and strategies with which to design a preventive intervention to introduce new drug preparation practices to reduce HIV and HCV transmission among IDUs. Upon termination of the proposed exploratory research, an R01 proposal will be designed to implement a field trial and test the diffusion, sustainability, and efficacy of the new drug preparation practices. [unreadable] [unreadable] [unreadable]